620.2 Pavement and Curb Markings (MUTCD Chapter 3B)

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620.2.1 Yellow Center Line Pavement Markings (MUTCD Section 3B.01)

Standard. Center line pavement markings, when used, shall be the pavement markings used to delineate the separation of traffic lanes that have opposite directions of travel on a roadway and shall be yellow.

The center line markings on two-lane, two-way roadways shall be one of the following as shown in Figure 620.2.1.1:

A. Two-direction passing zone markings consisting of a normal width broken (intermittent) yellow line where crossing the center line markings for passing with care is permitted for traffic traveling in either direction;
B. One-direction no-passing zone markings consisting of a double yellow line, one of which is a normal width broken (intermittent) yellow line and the other is a normal width solid yellow line, where crossing the center line markings for passing with care is permitted for the traffic traveling adjacent to the broken (intermittent) line, but is prohibited for traffic traveling adjacent to the solid line; or
C. Two-direction no-passing zone markings consisting of two normal width solid yellow lines where crossing the center line markings for passing is prohibited for traffic traveling in either direction.

A single solid yellow line shall not be used as a center line marking on a two-way roadway.

Except where a two-way left-turn lane (see EPG 620.2.6) is present, the center line markings on undivided two-way roadways with four or more lanes for moving motor vehicle traffic always available shall be the two-direction no-passing zone markings consisting of normal width double solid yellow lines separated by 4 in. as shown in Figure 620.2.1.2.

 

Figure 620.2.1.1 Yellow Center Lines for Two-Lane, Two-Way Applications

 

Figure 620.2.1.2 Yellow Center Lines for Four-or-More Lane, Two-Way Applications

Support. MoDOT previously marked center lines using a 2-line or 3-line system. The 3-line system is no longer used by MoDOT.

Standard. Highways that are currently marked using a 3-line center line marking system shall be maintained using the 3-line system until the center line markings are obliterated.

After a 3-line center line is obliterated from the entire route or a significant portion of the highway, the center line shall be replaced using the 2-line system.

EPG 620.2.13 contains information for application of pavement markings through intersections or interchanges.

Guidance. On two-way roadways with an additional climbing/truck lane in the upgrade direction, the opposing directions of traffic should be separated by using one-direction or two-direction no-passing zone markings.

Standard. On two-way roadways with alternating passing lanes, the opposing directions of traffic shall be separated by using two-direction no-passing zone markings (See Standard Plan 620).

Support. Examples of markings for alternating passing lanes are shown in Standard Plan 620.

620.2.2 Warrants for Yellow Center Lines (MUTCD Section 3B.02)

Standard. Center line markings shall be placed on all paved undivided two-way streets or highways that have a traveled way of 18 feet or more in width. Center line markings shall also be placed on all paved undivided two-way streets or highways that have three or more lanes for moving motor vehicle traffic.

Guidance. Engineering judgment should be used in determining whether to place center line markings on traveled ways that are less than 18 feet wide because of the potential for traffic encroaching on the pavement edges, traffic being affected by parked vehicles, and traffic encroaching into the opposing traffic lane. Engineering judgment should also be used to determine if the pavement can support center line markings.


Two examples of vertical, five-lane roadways are shown, with two southbound lanes on the left, two northbound lanes on the right, and a fifth center lane for left turns. At the top and bottom of the first example, the center lane is separated from the innermost through lanes by a solid white line on one side and a solid double yellow line on the other side. A left-turn arrow is shown between these lines in advance of intersecting cross streets. In the middle of this example, between the intersecting cross streets, in the center lane, an island is shown formed by solid double yellow lines on the outside and “optional yellow diagonal markings” on the inside. Below the island, the solid double yellow lines change to a solid yellow line on the outside and a broken yellow line on the inside. Two sets of opposing left-turn arrows are shown inside this pattern of broken and solid yellow lines. Continuing below the opposing left-turn arrow, this pattern changes to a double solid yellow on one side and a left-turn channel marked with an “optional dotted extension” followed by a solid white line on the other side. A single, left-turn arrow is shown between these pavement markings. The second example shows the center lane separated from the innermost through lanes with a pattern of broken yellow lines on the inside of solid yellow lines with two set of opposing left-turn arrows inside this pattern. Driveways are shown intersecting the vertical roadway at the locations of the opposing arrows. At the bottom of this example, south of the intersecting driveways, in the center lane, the pattern of broken and solid yellow lines changes to solid double yellow lines. A left-turn channel marked with an “optional dotted extension” followed by a solid white line is shown to separate the left-turn lane from the through traffic lanes just above another intersecting driveway. Two left-turn arrows are shown in between these pavement markings. South of this intersection, the center lane is shown separated by a solid white line and a solid double yellow line with a left-turn arrow in between.
Figure 620.2.2 Example of Two-Way, Left-Turn Marking Applications

620.2.3 No-Passing Zone Pavement Markings (MUTCD Section 3B.03)

Standard. No-passing zones shall be marked by either the one-direction no-passing zone pavement markings or the two-direction no-passing zone pavement markings described in EPG 620.2.1 and shown in Figure 620.2.1.1.

No-passing zone markings shall be used on:

A. Two-way roadways at lane-reduction transitions (see EPG 620.2.14),
B. Approaches to obstructions that must be passed on the right (see EPG 620.2.15),
C. Approaches to grade crossings (see EPG 913.3.2), and
D. Approaches to crosswalks.
E. Approaches to added uphill truck or passing lanes,
F. Approaches to controlled intersections, and
G. Approaches to lane transitions.

No-passing zone marking shall be installed a minimum of 500 feet in advance of conditions as described in the previous paragraph.


A horizontal roadway is shown with one lane in the eastbound direction and one lane in the westbound direction. An uphill truck lane is introduced in the eastbound direction. The pavement markings allow passing in the westbound direction and do not allow passing in the eastbound direction. In the right side of the figure, the uphill truck lane is terminated and the eastbound direction converts back to a single travel lane.
Figure 620.2.3.1 Marking Uphill Truck Lane


Option. The length of passing zone markings may be increased for sight distance limitations or based on engineering judgement.

Standard. On two-way, two-lane or non-continuous three-lane roadways, such as uphill truck or passing lanes, where center line markings are installed, no-passing zones shall be established at vertical and horizontal curves and other locations where an engineering study indicates that passing must be prohibited because of inadequate sight distances or other special conditions.

On roadways with center line markings, no-passing zone markings shall be used at horizontal or vertical curves where the passing sight distance is less than the minimum shown in Table 620.2.3 for the posted speed limit or the 85th-percentile speed.

Table 620.2.3 Minimum Passing Sight Distances for No-Passing Zone Markings
85th-Percentile or Speed Limit Minimum Passing Sight Distance
25 mph 500 feet
30 mph 500 feet
35 mph 550 feet
40 mph 600 feet
45 mph 700 feet
50 mph 800 feet
55 mph 900 feet
60 mph 1,000 feet
65 mph 1,100 feet
70 mph 1,200 feet


Figure 620.2.3.2 Method of Locating and Determining the Limits of No-Passing Zones at Curves


Support. The values of the minimum passing sight distance that are shown in Table 620.2.3 are for operational use in marking no-passing zones and are less than the values that are suggested for geometric design in the “AASHTO Green Book – A Policy On Geometric Design Of Highways And Streets”.

The passing sight distance on a vertical curve is the distance at which an object 3.5 feet above the pavement surface can be seen from a point 3.5 feet above the pavement (see Figure 620.2.3.2). Similarly, the passing sight distance on a horizontal curve is the distance measured along the center line (or right-hand lane line of a three-lane roadway) between two points 3.5 feet above the pavement on a line tangent to the embankment or other obstruction that cuts off the view on the inside of the curve (see Figure 620.2.3.2).

The upstream end of a no-passing zone at point “a” in Figure 620.2.3.2 is that point where the sight distance first becomes less than that specified in Table 620.2.3. The downstream end of the no-passing zone at point “b” in Figure 620.2.3.2 is that point at which the sight distance again becomes greater than the minimum specified.

Standard. Where the distance between successive no-passing zones is less than 500 feet, no-passing zone markings shall connect the zones. If the calculated no passing zone is less than 500 feet, an additional length of marking shall be added to the leading end of the zone to lengthen it to the full 500 feet.

Guidance. No-Passing Zone signs (see EPG 903.3.43) should not be installed without prior approval from the State Highway Safety and Traffic Engineer.

"Segments of a vertical three-lane roadway are shown. A solid double yellow line is shown separating each lane from the others with the notation “Two directional no passing marking.” At the top and bottom of the figure where one segment (two total) of a broken white line shown to separate the two southbound lanes and the two northbound lanes, respectively. From the top and bottom of the figure, two lanes are shown transitioning to one lane. Before the taper begins, a solid white arrow is shown marked on the pavement pointing diagonally to the outer edge of the outside travel lane. A solid double yellow line is shown adjacent to each outside lane in this taper. The length of this taper is shown and labeled “Buffer zone.” Each taper and buffer zone between the solid double yellow lines is shown with “optional yellow diagonal markings.”
Figure 620.2.3.3 Application of Three-Lane, Two-Way Markings for Changing the Direction of the Center Lane


Standard. On three-lane roadways where the direction of travel in the center lane transitions from one direction to the other, a no-passing buffer zone, consisting of a flush median island (see EPG 620.9.3) at least 50 feet in length, shall be provided in the center lane as shown in Figure 620.2.3.3. A lane-reduction transition (see EPG 620.2.14) shall be provided approaching each end of the buffer zone.

On multi-lane, undivided roadways with two or more lanes in each direction, a minimum of one double yellow center line shall be used to separate the opposing directions of travel. If pavement width is available, the preferred center line marking would provide a painted median formed by two double yellow center lines separated by a minimum of 12 inches to provide greater separation between opposing lanes of travel.

On continuous three-lane (passing lane) sections of roadway, the center line markings shall consist of two double yellow center lines separated by a minimum of 12 inches to separate the opposing directions of travel. See Figure 903.15.24 and EPG 232.2 for additional guidance on passing lanes.

On added uphill truck lanes, a no-passing zone marking shall be provided for the entire length of the ascending direction of travel.

For the descending direction of travel, no-passing zone markings shall be provided for a minimum length of 500 feet or ½ the taper length (L), whichever is greater, in advance of and beyond the location where the uphill truck lane becomes full width (see Figure 620.2.3.3). The length of any no-passing zone related to an uphill truck lane segment shall be increased to address sight distance limitations or based on engineering judgement.

Option. A passing zone may be provided in the descending direction of travel within the uphill truck lane full-width segment being based on available sight distance and engineering judgement.


Two examples of horizontal, four-lane roadways are shown, with two westbound lanes on the top, two eastbound lanes on the bottom, and an eastbound left turn lane. A left-turn arrow marking is shown in the turn lanes. Before the turn lanes, an island is shown formed by solid double yellow lines on the outside and on the inside. The first example shows the island in the median with a shifting taper with dimension label "L" towards the east before the beginning of the left-turn lane and also shows a closing taper one hundred feet from the beginning of the turn lane to the middle of the turn lane. The second example shows the island in the median similar to the first example except excluding the closing taper. A left-turn channel marked with an “optional dotted extension” followed by a solid white line is shown to separate the left-turn lane from the through traffic lanes.
Figure 620.2.3.4 Marking for Median Islands for Left Turn Bays


Standard. Median bubbles shall be marked using double yellow center lines to form both sides of the bubble at the beginning of a left turn bay where the bubble separates travel in opposite directions. Each installation of these markings will require individual treatment; therefore, no set dimensions have been established for their placement. Additional markings, such as diagonal lines inside the bubble, if used, shall also be yellow in color (See Figure 620.2.3.4).

Guidance. The taper length of transition zones should not be less than the taper length calculated using the equations L = WS or L = WS2/60 as defined in EPG 620.2.14. Installation of these markings should conform to the established general patterns.

620.2.4 Establishing and Recording No Passing Zones

Standard. The establishment of no passing zones shall be accomplished using two vehicles maintaining a predetermined distance. This distance will mark the beginning and end of the no passing zone section where a target 3.5 ft. above the road surface on the lead vehicle is just out of sight of the driver of the trailing vehicle, whose eye level is 3.5 ft. above the road surface. The use of a highly visible target, such as a flashing amber light, is recommended.

The line of sight used by the trailing vehicle observer shall remain within the limits of the pavement and/or shoulder. Due to current mowing practices, sight distance viewed across any other right of way can be obscured at various times of the year due to seasonal vegetation and right of way which has not been mowed (see Figure 620.2.3.2).

Guidance. The distance between the vehicles should be maintained constant and equal to the minimum passing sight distance value being used. A printed log of the no passing zone should be kept by the district office and copies given to the regional maintenance superintendents so no passing zones can be relocated after maintenance operations.

Support. The most effective way to maintain spacing between vehicles is to space the two vehicles apart the required sight distance and zero out the distance measuring equipment (DME). As the two vehicles move forward, the lead vehicle broadcasts the distance displayed on their DME to the trailing vehicle who works to match the distance on their DME device.

This method of determining no passing zones can be challenging and requires two vehicles, multiple people, and slower travel speeds to be accomplished safely. For longer road segments, on-call contractor-based measurement and reporting systems could be used.

620.2.5 Center Line Markings on Bridges

Standard. The center line markings on bridges, having a clear roadway width of 16 ft. or greater, shall be the same as that marked on the adjoining roadway.

Center line markings shall not be placed on one lane bridges. When dealing with this type of bridge, the center line markings shall stop a distance of 500 ft. from each edge of the bridge deck. Therefore, the length of surface not receiving center line marking shall be 1,000 ft. plus the length of the bridge deck. These bridges will, however, receive the appropriate one-lane bridge markings (see EPG 620.2.12).

620.2.6 Pavement Markings for Two-Way Left-Turn Lanes (MUTCD Section 3B.05)

Support. Two-way left turn lanes may be established by the district if the roadway meets all of the guidelines listed in EPG 232.3.

Standard. If a two-way left-turn lane is used, the lane line pavement markings on each side of the two-way left-turn lane shall consist of a normal width broken (intermittent) yellow line and a normal width solid yellow line to delineate the edges of a lane that can be used by traffic in either direction as part of a left-turn maneuver. These markings shall be placed with the broken (intermittent) line toward the two-way left-turn lane and the solid line toward the adjacent traffic lane as shown in Figure 620.2.2.

Standard. White two-way left-turn lane-use arrows shall be used at or just downstream from the beginning of a two-way left-turn lane to indicate the proper use of these lanes. The left-turn arrows shall be installed in pairs, one arrow per direction.

Guidance. The pairs of arrows should be installed a maximum of 500 ft. apart, with the two arrows in the pair being 8 to 16 ft. apart (see Figure 620.2.2) along a two-way left-turn lane.

Standard. A single-direction lane-use arrow shall not be used in a lane bordered on both sides by yellow two-way left-turn lane longitudinal markings.

Guidance. Signs should be used in conjunction with the two-way left-turn markings (see EPG 903.2.29).

Two-way left-turn lane markings should not extend to intersections (see definition in EPG 911 (MUTCD Section 1C.02)).

Option. Two-way left-turn lanes may be transitioned to mandatory left-turn lanes as shown in Figure 620.2.2 or painted median islands where they approach an intersection.

Support. EPG 913.1.6 contains guidance information for discontinuing a two-way left-turn lane in the immediate vicinity of a highway-rail or highway-LRT grade crossing.

620.2.7 White Lane Line Pavement Markings (MUTCD Section 3B.06)

Standard. When used, lane line pavement markings delineating the separation of traffic lanes that have the same direction of travel shall be white.

Lane line markings shall be used on all freeways and Interstate highways. Lane line markings shall be used on all roadways that are intended to operate with two or more adjacent traffic lanes in the same direction of travel.

Guidance. Lane lines should be offset approximately 2 in. from the longitudinal pavement joint. The 2 in. offset should be the space between the longitudinal joint and the edge of the lane line. See Standard Plan 620

Lane line markings should be used at congested locations where the roadway will accommodate more traffic lanes with lane line markings than without the markings.

The lane width delineated by lane line pavement markings should not be less than 10 feet.

Support. Examples of lane line markings are shown in Figure 620.2.1.2, and 620.2.2 through 620.2.7.2.

Standard. Except as provided in the first paragraph of EPG 620.2.8, where crossing the lane line markings with care is not discouraged or prohibited, the lane line markings shall consist of a normal width broken (intermittent) white line.

Broken (intermittent) white lane line pavement markings and dotted lane line markings on new concrete pavements shall be enhanced by the use of contrast markings (see EPG 620.1.3).

Where crossing the lane line markings is discouraged, the lane line markings shall consist of a normal width solid white line.

Guidance. A solid white lane line marking should be used on approaches to:

A. Intersections to separate a through lane from a mandatory turn lane.
B. Intersections to separate contiguous mandatory turn lanes from each other.
C. Channelized movements or obstructions.

Option. Solid white lane line markings may be used:

A. On approaches to intersections to separate contiguous through lanes.
B. To separate through traffic lanes from auxiliary lanes, such as an added uphill truck lane.
C. On approaches to crosswalks across multi-lane roadways.

Wide solid lane line markings may be used for greater emphasis.

A curved transition may be used where an edge line, channelizing line, or dotted extension line changes direction.

Support. Examples of locations where a curved transition can have value include freeway exit and entrance ramps, and turn lanes.

Standard. Where crossing the lane line markings is prohibited, the lane line markings shall consist of a solid double white line (DWL).

The State Highway Safety and Traffic Engineer must approve the use of a solid DWL.

Guidance. A solid DWL should be used to address an identifiable need.

Use signs in advance of the area delineated by a solid DWL to provide motorists an opportunity to adjust to the condition.

620.2.8 White Lane Line Markings for Non-Continuing Lanes (Section 3B.07)

Standard. A normal width dotted white line marking shall be used as the lane line to separate a through lane that continues beyond the interchange or intersection from an adjacent deceleration or acceleration lane.

For exit ramps with a parallel deceleration lane, a normal width dotted white lane line shall be installed from the upstream end of the taper to the theoretical gore or to the upstream end of a solid white lane line, if used, that extends upstream from the theoretical gore as shown in Drawings A and C in Figure 620.2.8.1 and 620.2.8.2.

For an exit ramp with a tapered deceleration lane, a normal width dotted white line extension shall be installed from the theoretical gore through the taper area such that it meets the edge line at the upstream end of the taper as shown in Drawing B in Figure 620.2.8.1.

For entrance ramps with a parallel acceleration lane, a normal width dotted white lane line shall be installed from the downstream end of a solid white lane line, if used, that extends downstream from the theoretical gore, to the upstream end of the acceleration taper, as shown in Drawing A in Figure 620.2.8.3.

Figure 620.2.8.1 Examples of Dotted Line and Channelizing Line Applications for Exit Ramp Markings (Sheet 1 of 2)

C. This example shows four northbound lanes of a vertical, divided highway. Near the bottom of this example, a deceleration lane is added to the right of the four northbound through lanes, leading to a right exit ramp. The deceleration lane runs parallel to the northbound through lanes and is separated from them by a dotted white line. The dotted white line changes to a "wide solid white lane line” in advance of the “theoretical gore.” At the theoretical gore, the “normal width or wide solid white lane line” continues along the exit ramp to the “physical gore” and a “normal width dotted white lane line” continues north toward a white triangle or neutral area. The exit lane is wide enough that the solid wide line is shown separating the left and right exit lanes. On the left side of the left exit lane, white channelizing lines form a white triangle or neutral area in front of the physical gore.
Figure 620.2.8.2 Examples of Dotted Line and Channelizing Line Applications for Exit Ramp Markings (Sheet 2 of 2)

"Two examples of two northbound lanes of a vertical, divided highway are shown.A. Near the bottom of this first example, a curving entrance ramp is added to the right of the through lanes, creating a parallel acceleration lane. Where the ramp joins the highway at the “physical gore,” the solid white line on the right edge of the right lane and the solid yellow line on the left edge of the entrance ramp become “wide white channelizing lines.” These lines form a triangle or “neutral area” in between them in front of the “physical gore.” The solid white line extending from the triangle or neutral area is labeled the “theoretical gore” and noted as a “wide or normal width solid white lane line (variable length) or normal width dotted white lane line.” The acceleration lane runs parallel to the rightmost through lane and is separated from it by a dotted white line. B. Near the bottom of this second example, an entrance ramp is added to the right of the right through lanes at an angle, creating a tapered acceleration lane. Where the ramp joins the highway at the “physical gore,” the solid white line on the right edge of the right through lane and the solid yellow line on the left edge of the entrance ramp become “wide white channelizing lines.” These lines then become a white triangle or neutral area north of the “physical gore.” The point of the triangle formed by the “wide white channelizing lines” is the “theoretical gore.” At this point, both the right through lane and the entrance lane are “full lane width.”"
Figure 620.2.8.3 Examples of Dotted Line and Channelizing Line Applications for Entrance Ramp Markings

This example shows a vertical highway with five northbound lanes. Four of the northbound lanes extend past an “exit ramp,” while the rightmost lane angles off to the right to become the exit ramp. In the middle of this example, the far-right lane is shown becoming the deceleration lane, leading to a right exit ramp. The deceleration lane is shown separated from the rightmost northbound through lane by a “wide dotted white lane line.” It is shown changing to an optional “wide solid white lane line” in advance of the “theoretical gore.” At the theoretical gore, the lane line joins the edge line from the right through lane to become “wide white channelizing lines” that then form a white triangle or neutral area in front of the “physical gore.” This triangle is shown with “white chevron markings in the neutral area.” The exit ramp angles away to the right.
Figure 620.2.8.4 Examples of Applications of Freeway and Expressway Lane-Drop Markings (Sheet 1 of 6)

This example shows a vertical highway with five northbound lanes. Four of the northbound lanes extend past an exit ramp, and the rightmost lane angles off to the right to become the exit ramp. In the middle of the example, the far-right lane becomes the deceleration lane, leading to a right exit ramp. The deceleration lane is shown separated from the rightmost northbound through lane by a “wide dotted white lane line.” It is shown changing to a “wide solid white lane line” in advance of the “theoretical gore.” At the theoretical gore, the lane line continues along the exit ramp to the “physical gore”. The exit lane is wide enough that the solid white line is shown separating the left and right exit lanes. On the left side of the left exit lane, the lane line joins the edge line from the right through lane to become “wide white channelizing lines” that then form a white triangle or neutral area in front of the physical gore.
Figure 620.2.8.5 Examples of Applications of Freeway and Expressway Lane-Drop Markings (Sheet 2 of 6)

This example shows a vertical highway with four northbound lanes. Two of the northbound lanes extend past an exit ramp, and the two rightmost lanes angle off to the right to become an exit ramp. Near the bottom of the example, the two rightmost lanes are shown becoming the deceleration lanes, leading to a right exit ramp. The deceleration lanes are shown separated from the rightmost of the two remaining northbound through lanes by a “wide dotted white lane line.” It is shown changing to a “wide solid white lane line” in advance of the “theoretical gore.” The right exit ramp is wide enough that the broken white line is shown separating the left and right exit lanes. On the left side of the left exit lane, the lane line joins the edge line from the right through lane to become “wide white channelizing lines” that then form a white triangle or neutral area in front of the “physical gore.”
Figure 620.2.8.6 Examples of Applications of Freeway and Expressway Lane-Drop Markings (Sheet 3 of 6)

This example shows a vertical highway with four northbound lanes. Two of the northbound lanes split to the left and two split to the right. Near the bottom of this example, the two leftmost northbound lanes are shown separated from the two rightmost lanes by a “wide dotted white lane line.” The dotted lane line changes to a “wide solid white lane line” in advance of a “theoretical gore.” The lane line splits into two “wide white channelizing lines” that then form a white triangle or neutral area in front of the “physical gore” between the left and right lanes. Beyond the physical gore, two through lanes curve to the left and two curve right.
Figure 620.2.8.7 Examples of Applications of Freeway and Expressway Lane-Drop Markings (Sheet 4 of 6)

This example shows a vertical highway with three northbound lanes, where the left northbound lane splits to the left, the middle lane has the option of splitting to the left or right, and the right lane splits to the right. Near the bottom of this example, the right lane is shown separated from the middle lane by a “wide dotted white lane line.” The dotted lane line is shown changing to a “wide solid white lane line” as it curves to the right. The middle lane splits to the right with the right lane. The middle lane splits to the left and continues north with the left lane. Beyond the neutral area and physical gore, two through lanes continue north to the left and two lanes curve to the right.
Figure 620.2.8.8 Examples of Applications of Freeway and Expressway Lane-Drop Markings (Sheet 5 of 6)

This example shows two northbound lanes of a divided vertical highway with an auxiliary lane in between an entrance ramp at the bottom of this example and an exit ramp at the top of this example. Near the bottom of this example, a curving entrance ramp is added to the right of the through lanes. Where the ramp joins the highway, the solid white line on the right edge of the right lane and the solid yellow line on the left edge of the entrance ramp become wide solid white lines that then become a white triangle or neutral area in front of the “physical gore.” These solid lines then become “white channelizing lines” that join at the “theoretical gore” and continue as a “wide solid white lane line.” This auxiliary lane runs parallel to the rightmost through lane and is separated from it by a dotted white line. Further north, the dotted white line changes to a “wide solid white lane line” in advance of the “theoretical gore” at an exit ramp to the right. The auxiliary lane angles to the right to become the exit ramp. On the left side of the exit ramp, the white lane line joins the white edge line from the right through lane to become “wide white channelizing lines” that then form a white triangle or neutral area in front of the “physical gore.”
Figure 620.2.8.9 Examples of Applications of Freeway and Expressway Lane-Drop Markings (Sheet 6 of 6)


Segments of the northbound lanes of a vertical highway are shown. At the bottom of the example, three northbound through lanes are shown. A left-turn lane is shown in addition to the through lanes in advance of the intersection, and a white stop line is shown across all four lanes of the vertical highway at the intersection. At the top of the figure, a horizontal roadway is shown intersecting the vertical highway, which continues north of the intersection as only two through lanes. On the vertical roadway, near the bottom of the figure, the broken white line separating the right lane from the middle lane changes to a wide dotted white lane line, which changes to a wide solid white lane line further north. Where the “wide solid white lane line” begins, between the right-turn lane and right through lane traveling northbound, the word “ONLY” in white is shown on the pavement, followed by a solid white right-turn arrow, the word “ONLY” again, and another right-turn arrow at the stop line at the intersection. This right-turn lane is not shown continuing on the north side of the intersection. Where the “wide solid white lane line” begins between the right-turn lane and right through lane, a left-turn lane is shown to the left of the left through lane. A white left-turn arrow is shown on the pavement in this lane, followed by a second left-turn arrow near the intersection. Closer to the intersection, the white dotted line is shown as a solid white lane line, continuing to the stop line at the intersection. This left-turn lane is not shown continuing on the north side of the intersection. Size, location, and spacing distances between pavement markings are shown. The broken white line between the through lanes changes to a solid white lane line closer to the intersection. These two lanes are shown continuing on the north side of the intersection.
Figure 620.2.8.10 Examples of Applications of Conventional Road Lane-Drop Markings (Sheet 1 of 2)

Figure 620.2.8.11 Examples of Applications of Conventional Road Lane-Drop Markings (Sheet 2 of 2)

Option. For entrance ramps with a parallel acceleration lane, a normal width dotted white line extension may be installed from the upstream end of the acceleration taper to the downstream end of the acceleration taper, as shown in Drawing A in Figure 620.2.8.3.

For entrance ramps with a tapered acceleration lane, a normal width dotted white line extension may be installed from the downstream end of the channelizing line adjacent to the through lane to the downstream end of the acceleration taper, as shown in Drawing B in Figure 620.2.8.3.

Standard. A wide dotted white lane line shall be used:

A. As a lane drop marking in advance of lane drops at exit ramps to distinguish a lane drop from a normal exit ramp (see Drawings A, B, and C in Figures 620.2.8.4 through 620.2.8.6),
B. In advance of freeway route splits with dedicated lanes (see Drawing D in Figure 620.2.8.7),
C. In advance of freeway route splits with an option lane (see Drawing E in Figure 620.2.8.8),
D. To separate a through lane that continues beyond an interchange from an adjacent continuous auxiliary lane between an entrance ramp and an exit ramp (see Drawing F in Figure 620.2.8.9),
E. As a lane drop marking in advance of lane drops at intersections to distinguish a lane drop from an intersection through lane (see Drawing A in Figure 620.2.8.10), and
F. To separate a through lane that continues beyond an intersection from an adjacent auxiliary lane between two intersections (see Drawing B in Figure 620.2.8.11).

The dotted white lane lines that are used for lane drop markings and that are used as a lane line separating through lanes from auxiliary lanes shall consist of line segments that are 3 feet in length separated by 9-foot gaps.

Guidance. Lane drop markings used in advance of lane drops at freeway and expressway exit ramps should begin at least ½ mile in advance of the theoretical gore.

Option. On the approach to a multi-lane exit ramp having an optional exit lane that also carries through traffic, lane line markings may be used as illustrated in Drawing B in Figure 620.2.8.5.

Guidance. Lane drop markings used in advance of lane drops at intersections should begin a distance in advance of the intersection that is determined by engineering judgment as suitable to enable drivers who do not desire to make the mandatory turn to move out of the lane being dropped prior to reaching the queue of vehicles that are waiting to make the turn. The lane drop markings should begin no closer to the intersection than the most upstream regulatory or warning sign associated with the lane drop.

Support. EPG 620.2.20 and 620.2.22 contain information regarding other markings that are associated with lane drops, such as ONLY word pavement markings and lane-use arrows.

EPG 620.2.14 contains information about the lane line markings that are to be used for transition areas where the number of through lanes is reduced at a location that is not at an interchange or intersection.

Option. In the case of a lane drop at an exit ramp or intersection, a solid white line may replace a portion, but not all of the length, of the wide dotted white lane line (See Figures 620.2.8.4 through 620.2.8.9).

620.2.9 Channelizing Lines (MUTCD Section 3B.08)

Support. Channelizing lines are used to form neutral areas where traffic traveling in the same general direction is permitted on both sides including entrance and exit ramps, access and egress points to and from managed lanes, and left-turn lanes separated from through lanes. Channelizing lines are also sometimes used to alter travel paths for speed management or other purposes.

EPG 620.9 contains information for the application of channelizing lines used in conjunction with islands.

Standard. Except as provided in the third Option paragraph of EPG 620.9.5, a channelizing line shall be a solid wide white line.

Channelizing lines used to mark gores shall be wide solid white lines.

Support. Examples of channelizing line applications are shown in Figures 620.2.8.2, 620.2.8.3, 620.2.8.4, Drawing C in Figure 620.2.15.2, Figures 620.9.2 through 620.9.4.4, and Figure 620.9.7.

Standard. For all exit ramps and for entrance ramps with parallel acceleration lanes, channelizing lines shall be placed on both sides of the neutral area (see Figure 620.2.8.1, Figure 620.2.8.2, Drawing A in Figure 620.2.8.3, and Figures 620.2.8.4 through 620.2.8.9).

For entrance ramps with tapered acceleration lanes, the channelizing lines shall extend to the theoretical gore as shown in Drawing B in Figure 620.2.8.3.

Other pavement markings in the neutral area shall be white.

Support. Pavement markings within the neutral area include chevron markings (see EPG 620.2.24).

620.2.10 Edge Line Pavement Markings (MUTCD Section 3B.09)

Standard. If used, edge line pavement markings shall delineate the right or left edges of a roadway.

Except as provided in EPG 620.5.4, right edge line pavement markings, if used, shall consist of a normal width solid white line to delineate the right-hand edge of the roadway.

If used on the roadways of divided highways or one-way streets, or on any ramp in the direction of travel, left edge line pavement markings shall consist of a normal width solid yellow line to delineate the left-hand edge of a roadway or to indicate driving or passing restrictions left of these markings, except as provided in EPG 620.5.4.

Guidance. When solid wide lines are used at entrance or exit ramps, the additional width of the wide line should encroach on the through lane of the highway (see Figure 620.2.10).

Support. Edge line markings provide visual references to guide road users during adverse weather and visibility conditions.

Guidance. Edge line markings should not be continued through intersections, except for the following situations:

A. Dotted edge line extensions (see EPG 620.2.13), or
B. Through that part of an intersection with no intersection approach (such as the far side of a T-intersection).

Support. EPG 620.2.13 contains information on the use and application of edge lines through intersections, interchanges, and driveways.

Figure 620.2.10 Example of Channelizing Line Markings at Ramp Gores

620.2.11 Warrants for Use of Edge Lines (MUTCD Section 3B.10)

Standard. Edge line markings shall be placed on paved streets or highways with the following characteristics:

A. Freeways,
B. Expressways, and
C. Routes with a traveled way of 20 feet or more in width and an ADT of 400 vehicles per day or greater.

Option. Edge line markings may be excluded, based on engineering judgment, for reasons such as if the traveled way edges are delineated by curbs, parking, or other markings.

If a bicycle lane is marked on the outside portion of the traveled way, the edge line that would mark the outside edge of the bicycle lane may be omitted.

Edge line markings may be used where edge delineation is desirable to minimize unnecessary driving on paved shoulders or on refuge areas that have lesser structural pavement strength than the adjacent roadway.

620.2.12 Bridge Edge Lines

Standard. Bridges that are located on routes authorized for edge lines shall be striped in accordance with the following classifications (see Figure 620.2.12.1 and Figure 620.2.12.2):

A. Non-shoulder width bridges that have been constructed with a deck less than 2 ft. wider than the adjacent roadway on each side of the pavement shall not have the edge line placed on the bridge deck. The edge line shall end on the adjacent roadway 50 ft. from the bridge deck.
B. Bridges wider than the roadway pavement by more than 2 ft. on each side shall receive edge line that will be continuous with that of the adjoining roadway.
C. Three lane bridges designed and constructed with an additional lane for future use shall be marked as a two lane bridge. The edge line in these cases shall not be offset to provide for the usage of the third lane and the edge line will be continuous across the bridge.
D. One lane, weight restricted bridges have a reduced driving surface due to an inability to carry the weight of two lanes of traffic. These bridges shall be marked using a wide white edge line that forms a 12 ft. travel lane on the bridge deck. These edge lines shall then taper from the edge of the bridge deck 200 ft. to the edge of the roadway pavement. The center line marking, if applicable, shall end 500 ft. from the end of the bridge deck.
E. One lane bridges with width restrictions, having a clear traveling surface 16 ft. or less shall be marked using a wide white edge line that forms a 12 ft. travel lane on the bridge deck. These edge lines shall then taper from the edge of the bridge deck 200 ft. to the edge of the roadway pavement. The center line marking, if applicable, shall end 500 ft. from the end of the bridge deck.

Guidance. Special attention should be given to all bridges whose shoulders are 2 ft. or wider than the shoulders of the adjacent roadway.

Standard. If bridges whose shoulders are 2 ft. or wider than the shoulders of the adjacent roadway are on routes authorized for center line marking, but not edge line marking, a segment of edge line shall be marked to delineate the travel way of the bridge. The edge line marking for these bridges shall begin 500 ft. ahead of, and end 500 ft. beyond, the bridge deck. These markings are intended to guide vehicles from the wider bridge deck to the narrower adjacent roadway (see Figure 620.2.12.1 and Figure 620.2.12.2.)

Figure 620.2.12.1 Edge Line Striping for Two-Lane, Two-Way Bridges

Figure 620.2.12.2 Edge Line Striping for Single Lane Bridges

620.2.13 Application of Pavement Markings Through Intersections or Interchanges (MUTCD Section 3B.11)

Standard. Pavement markings extended into or continued through an intersection or interchange area shall be the same color as the line markings they extend (see Figure 620.2.13.1 and Figure 620.2.13.2).

Intersections that provide more than one turn lane per movement shall have dotted extension lines for traffic to follow through the intersection, except as provided in the following Option paragraph. These lines shall be marked with dotted extension lines (2-foot line segments separated by 4-foot gaps), and shall follow the appropriate turning radius of the intersection. This line shall begin at the solid white lane line of the left turn bay and end at the lane line delineating the lanes the traffic is being channelized to. Dotted extension lines shall not be marked within crosswalks.

Option. Exceptions will be allowed when the dotted extension lines for opposing dual left-turn movements overlap in a manner that may cause driver confusion.

Guidance. Pavement markings extended into or continued through an intersection or interchange area should be at least the same width as the line markings they extend.

Where highway design or reduced visibility conditions make it desirable to provide control or to guide vehicles through an intersection or interchange, such as at offset, skewed, complex, or multi-leg intersections, on curved roadways, where multiple turn lanes are used, or where offset left-turn lanes might cause driver confusion, dotted lane line extension markings consisting of 2-foot line segments and 4-foot gaps should be used to extend longitudinal line markings through an intersection or interchange area.

In areas of limited sight distance due to vertical and/or horizontal curves, an edge line extension may be used to delineate acceleration and deceleration lanes.

Standard. Extensions of center lines through intersections shall be dotted lines.

Guidance. Where a double line is extended through an intersection, a single line of equal width to one of the lines of the double line should be used.

Standard. Solid lines shall not be used to extend edge lines into or through intersections except through that part of an intersection with no intersecting approach (such as at the far side of a T-intersection).

Guidance. Edge line markings should be discontinued across intersecting approaches at intersections or interchanges.

Driveways that do not meet the definition of an intersection (see EPG 911 (MUTCD Section 1C.02)) should have edge line markings maintained across the intersecting approach of the driveway.

Option. Dotted edge line extensions may be placed through intersections.

Edge line extension lines may be used at the district's discretion.

Guidance. Durable pavement markings should be used for edge line extensions. An attempt should be made to keep the painted portion of this line out of the wheel tracks to promote longer life.

For a divided highway, the edge line at an intersection should begin and end at the taper points when the intersection has no deceleration lanes. Where deceleration lanes are present, the edge line should continue along the outside of the deceleration lane to the beginning of the turn radius (see Figure 620.2.13.3).

Figure 620.2.13.1 Examples of Line Extensions through Intersections (Sheet 1 of 2)

Figure 620.2.13.2 Examples of Line Extensions through Intersections (Sheet 2 of 2)


Figure 620.2.13.3 Edge Line Striping for At Grade Intersections

Support. EPG 620.2.30 contains information about edge lines through diverging diamond interchanges with a transposed alignment crossroad.

EPG 620.4.3 provides information for edge lines through roundabouts.

EPG 912 (MUTCD Section 5B.02) contains information on edge line extensions for driving automation system considerations.

EPG 913.3.5 contains information about the extension of edge lines through grade crossing areas.

EPG 914.5.3 contains information for the extensions of bicycle lanes through intersections.

620.2.14 Lane-Reduction Transitions (MUTCD Section 3B.12)

Figure 620.2.14 Examples of Applications of Lane-Reduction Transition Markings

Support. A lane-reduction is where the number of through lanes is reduced at a location that is not at an interchange, ramp, or intersection because of narrowing of the roadway or because of a section of on-street parking in what would otherwise be a through lane.

EPG 620.2.8 contains information on pavement markings for lane drops and splits.

EPG 903.3.39 contains information for warning signing used for lane reductions.

Standard. Lane-reduction transitions (see Figure 620.2.14) shall include the following elements:

A. A no-passing zone (see EPG 620.2.3) to prohibit passing in the direction of the convergence and through the transition area except where not applicable such as one-way streets, expressways, and freeways; and
B. An edge line (see EPG 620.2.10) in the direction of the convergence and through the transition area, except as provided in the first Option paragraph below.

Guidance. Except as provided in the following Option paragraph, the edge line marking should be installed from the location of the Lane Ends warning sign to beyond the beginning of the narrower roadway.

Option. On roadways with operating speeds less than 25 mph where curbs clearly define the roadway edge in the lane-reduction transition, or where a through lane becomes a parking lane, the edge line may be omitted as determined by engineering judgment.

Guidance. Lane-reduction transitions should include the following elements:

A. Delineators installed adjacent to the lane or lanes reduced for the full length of the transition and should be so placed and spaced (see EPG 620.6.4) to show the reduction except as provided in the third Option paragraph below and except as provided in the second paragraph of EPG 620.6.3 for freeways and expressways,
B. Lane-reduction arrow markings (see Drawing H in Figure 620.2.22.1) on the roadway with a speed limit of 45 mph or more, and
C. A termination of the broken (intermittent) white lane line at a point that is ¼ of the advance placement distance (see EPG 903.3.4) between the Lane Ends sign (see EPG 903.3.39) and the point where the transition taper begins.

For roadways having a speed limit of 45 mph or greater, the transition taper length for a lane-reduction transition should be computed by the formula L = WS, where L equals the taper length in feet, W equals the width of the offset distance in feet, and S equals the 85th-percentile speed or the speed limit in mph, whichever is higher. For roadways where the speed limit is less than 45 mph, the formula L = WS2/60 should be used to compute the taper length.

The minimum lane reduction transition taper length should be 100 feet in urban areas and 200 feet in rural areas.

Where observed speeds exceed speed limits, longer tapers should be used.

Option. The minimum taper length may be less than 100 feet on roadways where the operating speed is less than 25 mph.

On new construction, where no speed limit has been established, the design speed may be used in the transition taper length formula.

On low-speed urban roadways where curbs clearly define the roadway edge in the lane-reduction transition, or where a through lane becomes a parking lane, delineators may be omitted as determined by engineering judgment.

Where a lane-reduction transition occurs on a roadway with a speed limit of less than 45 mph, lane-reduction arrow markings may be used.

Lane-reduction arrow markings may be used in long acceleration lanes based on engineering judgment.

620.2.15 Approach Markings for Obstructions (MUTCD Section 3B.13)

Standard. Pavement markings shall be used to guide traffic away from fixed obstructions within a paved roadway. Approach markings for bridge supports, refuge islands, median islands, and raised channelization islands shall consist of a tapered line or lines extending from the center line or the lane line to a point 1 to 2 feet to the right-hand side, or to both sides, of the approach end of the obstruction (see Figure 620.2.15.1 and Figure 620.2.15.2).


Figure 620.2.15.1 Examples of Applications of Markings for Obstructions in the Roadway
(Sheet 1 of 2)


Figure 620.2.15.2 Examples of Applications of Markings for Obstructions in the Roadway
(Sheet 2 of 2)


Guidance. For roadways having a speed limit of 45 mph or greater, the taper length of the tapered line markings should be computed by the formula L = WS, where L equals the taper length in feet, W equals the width of the offset distance in feet, and S equals the 85th-percentile speed or the speed limit, whichever is higher. For roadways where the speed limit is less than 45 mph, the formula L = WS2/60 should be used to compute the taper length.

The minimum taper length should be 100 feet in urban areas and 200 feet in rural areas.

Option. The minimum taper length may be less than 100 feet on roadways where the operating speed is less than 25 mph.

Observed speeds may be used to determine the taper length when the observed speed exceeds the posted or statutory speed limits.

Unique situations may require special markings or warning devices.

Standard. If traffic is required to pass only to the right of the obstruction, the markings shall consist of a two-direction no-passing zone marking at least twice the length of the diagonal portion as determined by the appropriate taper formula (see Drawing A in Figure 620.2.15.1).

Option. If traffic is required to pass only to the right of the obstruction, yellow diagonal markings (see EPG 620.2.24) may be placed in the flush median islands (see EPG 620.9.3) between the no-passing zone markings as shown in Drawings A and B in Figure 620.2.15.1.

Standard. If traffic can pass either to the right or left of the obstruction, the markings shall consist of two channelizing lines diverging from the lane line, one to each side of the obstruction. In advance of the point of divergence, a wide solid white line shall be extended in place of the broken (intermittent) lane line for a distance equal to the length of the diverging lines (see Drawing C in Figure 620.2.15.2).

Option. If traffic can pass either to the right or left of the obstruction, additional white chevron markings (see EPG 620.2.24) may be placed in the flush neutral area between the channelizing lines as shown in Drawing C in Figure 620.2.15.2. Other markings, such as white delineators, white channelizing devices, and white crosswalk markings may also be placed in the flush neutral area.

The obstruction and marking may, if possible, be illuminated by overhead lighting that will adequately light the object without directing glare toward road users approaching from either direction.

Support. EPG 903.3.71 contains information regarding object markers for obstructions within the roadway.

620.2.16 Inlaid Pavement Markers – General (MUTCD Section 3B.14)

An example of ambient light obscuring pavement markings, but also an example of ILPMs also not working due to the flat grade of the highway not allowing the grooves the ILPMs are installed in to drain, resulting in the markers becoming submerged and rendered ineffective.

Support. MoDOT has utilized a series of various pavement marking systems to enhance wet night visibility over the decades, including snow plowable raised pavement markers, rumble stripe edge lines, grooved in durable markings with wet reflective elements, grooved in waterborne markings with wet elements and the current marking system using an enhanced ASTM Type III glass bead (MoDOT Type L) on all pavement markings on major roads. The MoDOT Type L / high build waterborne pavement marking and edge line rumble stripes are the predominate wet nighttime marking system, with inlaid pavement markers being an optional supplement to this system.

Inlaid pavement markers (ILPMs) offer benefits over traditional pavement markings in heavy rain conditions, and in conditions where ambient light creates a sheen on the wet pavement at night making it more difficult to see traditional pavement markings. However, ILPMs are only a supplement to traditional pavement markings, which must be maintained at the highest standards possible. ILPMs only serve as a supplement as they provide no guidance during daylight hours, and pavement markers provide no guidance to the machine vision systems that are being deployed in today’s vehicle fleet.

ILPMs can provide a safety benefit during wet-night conditions where they are warranted. However, research indicates ILPMs can have a negative safety impact if applied in areas where they are not warranted, providing too much guidance resulting in drivers overdriving the wet-night conditions. The research found the markers to offer the greatest safety impact in urban areas on divided highways with three or more lanes in one direction and areas where ambient light creates a sheen on the pavement obscuring normal pavement markings. With MoDOT’s direction to use rumble stripes for all its major roadways, roads with only two lanes in each direction offer the enhanced edge line guidance to all lanes of traffic compared to a three-lane section where the middle lane has no edge line rumble stripe to reference.

Installations are being limited to the cradle system of ILPMs at this time as they have proven to provide the longest service life compared to other systems which have been evaluated. The reflectors are installed in pairs to provide redundancy and increase the service life of the installation.

ILPMs are not without limitations, these devices are recessed below the pavement surface to protect the reflectors from snowplow damage. On roadway segments with a grade or super elevation in a curve, the grooves the markers are installed in will typically drain keeping the reflectors visible. However, on roadway segments which have a flat grade these grooves can fill up with water covering the reflectors rendering them ineffective in heavier rain events.


MoDOT's Implementation of ILPMs

Standard. If used, ILPMs shall be installed according to the following conditions:

A. ILPMs are limited to freeways with three or more through lanes in one direction.
B. The cradle system of ILPMs shall be the marker style used. ILPMs shall comply with the current approved vendor list.
C. ILPMs shall be installed in pairs, placed in every other gap between the skips of broken (intermittent) lane line markings only when:
  1. Installed in accordance with manufactures’ installation guidance.
  2. Special attention needs to be given to installations on concrete as ILPM installations in concrete have historically had high failure rates. The selected manufacturer must demonstrate they have corrected this issue with an appropriate installation procedure.
D. The ILPMs shall contain a white reflector visible to oncoming traffic and a red reflector on the reverse side of the marker, providing a wrong way deterrent. The color of the ILPMs shall conform to the color of the marking they supplement, under both daylight and nighttime conditions. When used, ILPMs shall require approval from the State Highway Safety and Traffic Engineer.
ILPM installation in pavement groove
Paired ILPM installation and spacing
Newly installed cradle ILPM, cradle tabs still in place which hold the marker at the proper elevation until the epoxy cures
Paired ILPM installation and spacing

Support. ILPMs do have a limited life expectancy, when installed in accordance with the guidance above, the service life is approximately 4 to 5 years or roughly half the life of a typical asphalt overlay. Failure modes can include damage / missing reflector lenses from the cradle, or the loss of the entire reflector installation from the pavement. Loss of the entire marker installation results in a cavity in the pavement which could accelerate pavement deterioration.

Guidance. Maintenance and impacts to pavement should be taken into account when considering the installation of ILPMs. A maintenance program should be implemented to maintain the marker’s performance. This maintenance should take place approximately halfway through the asphalt’s overlay cycle, assuming an 8 to 10 year cycle.

Support. Concrete installation maintenance requirements can be significantly different due to the service life of a concrete surface. Based on maintenance cycles from other states, this would typically result in maintenance beginning 4 years after the initial installation, a second maintenance cycle 2-3 years later and then annually from that point forward. This cycle accounts for the varying ages of markers that results from the lack of an overlay replacement. The actual maintenance cycle may vary based on inspections. The use of MoDOT’s mobile retroreflectivity contract could also be used to measure ILPM performance to determine the maintenance needs.

Option. Maintenance of ILPMs in asphalt may be accomplished in two typical fashions:

A. Install new ILPMs in the gaps between lane lines which did not receive markers initially, allowing the original markers to fade out of service. This is the more efficient and cost effective method, however, milling new markers into a midlife asphalt could accelerating the asphalt joint failure depending on pavement condition.
B. Inspection and replace ILMPs individually in their original locations. This method is more labor intensive and costly; however, it could reduce the risk of accelerated pavement failure by eliminating new milling operations. Reinstalling markers in the cavities left by old, dislodged markers could also help seal and preserve the pavement.

Guidance. When districts consider the use of ILPMs, they should answer the following questions:

A. Does the route in question have a documented wet-night crash history that is tied to visibility and not surface condition to warrant the installation?
B. Will the installations be planned to be maintained or will the initial installation be allowed to fade out of service?
C. If the installation will be allowed to fade out of service, what ramifications would a district expect in terms of failing to meet customer expectations for the presence of the markers and/or increases in wet-night crashes as markers fade away?
D. Will the benefits of installing ILPMs offset the impacts to the pavement and its long term maintenance?
Missing reflector from cradle, new reflector can be reinstalled to maintain
Complete loss of marker installation, these sites need to be patched with asphalt or new markers installed in the same location

620.2.17 Curb Markings for Delineation (MUTCD Section 3B.18)

Option. Barrier curbs on the outside shoulder with a minimum height of 6 inches may be marked for the purpose of delineation.

Guidance. Barrier curbs which are located in the line of traffic flow where the curb serves to channel traffic should be marked, even in cases in which they otherwise would not be marked as indicated in the following paragraph.

Curbs should not be marked in the following cases:

A. Where the posted speed limit is 40 mph or less.
B. Curbs that diverge from the normal traffic flow for commercial and private entrances.
C. Curbs that are mountable (see Standard Plan 609).

Option. The first 200 ft. of a barrier curb may also be painted in the above cases to mark the beginning of these barriers (See Figure 620.2.17).

Figure 620.2.17 Painted Curb Marking for Barrier Curbs


Guidance. Since yellow and white curb markings are used for curb delineation and visibility, parking regulations should be established through the installation of standard signs (see EPG 903.2.43 and EPG 903.2.44).

620.2.18 Stop and Yield Lines (MUTCD Section 3B.19)

Option. Stop lines may be used to indicate the point behind which vehicles are required to stop in compliance with a STOP (R1-1) sign or some other traffic control device that requires vehicles to stop, except YIELD signs that are not associated with passive grade crossings.

Standard. Stop lines shall consist of solid white lines extending across approach lanes to indicate the point at which the stop is intended or required to be made.

Except as provided in EPG 913.3.3, stop lines shall not be used at locations where drivers are required to yield in compliance with a YIELD (R1-2) sign, a Yield Here to Pedestrians (R1-5) sign, a Yield Here to School Crossings (R1-5a) sign, a Yield Here to Trail Crossings (R1-5d) sign, or at locations on uncontrolled approaches where drivers or bicyclists are required by State law to yield to pedestrians.

Guidance. Stop lines should be used to indicate the point behind which vehicles are required to stop in compliance with a traffic control signal (see EPG 902.4.8).

Standard. Stop lines shall be 24 inches wide.

Option. Stop lines may be omitted at ramp control signals.

Support. EPG 902.10.2 contains information regarding the use and application of stop lines in conjunction with a pedestrian hybrid beacon.


Figure 620.2.18 Examples of Yield Line Applications

Standard. If used, a yield line pavement marking shall not be installed without a Yield (R1-2) sign, a Yield Here to Pedestrians (R1-5) sign, a Yield Here to School Crossings (R1-5a) sign, a Yield Here to Trail Crossings (R1-5d) sign, or some other traffic control device that requires vehicles to yield (see Figure 620.2.18).

Yield lines shall not be used at locations where drivers are required to stop in compliance with a STOP (R1-1) sign, a traffic control signal, or some other traffic control device.

Yield lines shall consist of a row of solid white isosceles triangles pointing toward approaching vehicles extending across approach lanes to indicate the point at which the yield is intended or required to be made.

The individual triangles comprising the yield line shall have a base of 24 inches wide and a height of 36 inches. The space between the triangles shall be 8 to 12 inches. The spacing of triangles in a yield line shall be consistent for that marking. See Standard Plan 620.

Option. Yield lines may be considered for those locations where a channelized right turn lane is developed but there is not an acceleration lane on the intersecting road.

Yield lines may also be used where engineering judgment indicates a need.

Guidance. If used, stop and yield lines should be placed a minimum of 4 feet in advance of the nearest crosswalk line at controlled intersections, except for yield lines at roundabouts as provided for in EPG 620.4.4 and at midblock crosswalks. Stop lines can be adjusted using engineering judgement to accommodate pedestrian facilities or improve safety, but the stop line in the lane closest to the right-hand edge of the roadway should be placed a maximum of 10 feet in advance of the nearest crosswalk. In the absence of a marked crosswalk, the stop line or yield line should be placed at the desired stopping or yielding point, but should not be placed more than 30 feet or less than 4 feet from the nearest edge of the intersecting traveled way.

Stop lines should be placed to allow sufficient sight distance to all other approaches to an intersection.

When a stop line is used in conjunction with the STOP sign it should be placed adjacent to, or in line with, the STOP sign.

When a yield line is used in conjunction with the YIELD sign it should be placed adjacent to, or in line with, the YIELD sign.

Standard. If yield lines are used at a crosswalk that crosses an uncontrolled multi-lane approach, Yield Here to Pedestrians (R1-5 series) signs (see EPG 903.2.18) shall be used.

Guidance. If yield lines are used at a crosswalk that crosses an uncontrolled multi-lane approach, the yield line should be placed 20 to 50 feet in advance of the nearest crosswalk line (see Drawing B in Figure 620.2.18).

If yield lines are used in advance of a crosswalk that crosses an uncontrolled multi-lane approach, parking should be prohibited in the area between the yield line and the crosswalk.

Guidance. Yield lines and Yield Here to Pedestrians signs should not be used in advance of crosswalks that cross an approach to or departure from a circular intersection.

Support. EPG 913.3.3 contains information regarding the use of stop lines and yield lines at grade crossings.

Option. Stop and yield lines may be staggered longitudinally on a lane-by-lane basis (see Drawing D in Figure 620.2.13.2).

Support. Staggered stop lines and staggered yield lines can improve the driver’s view of pedestrians, provide better sight distance for turning vehicles, and increase the turning radius for left-turning vehicles.

620.2.19 Word, Symbol, and Arrow Pavement Markings – General (MUTCD Section 3B.20)

Support. Word, symbol, and arrow markings on the pavement are used for the purpose of regulating, warning, or guiding traffic. These pavement markings can be helpful to road users in some locations by supplementing signs and providing additional emphasis for important regulatory, warning, or guidance messages, because the markings do not require diversion of the road user’s attention from the roadway surface. Symbol messages are preferable to word messages. Examples of standard word and arrow pavement markings are shown in Figure 620.2.20 and Figure 620.2.22.1, respectively. See Standard Plan 620.

Option. Word, symbol, and arrow pavement markings may be used as determined by engineering judgment to supplement signs and/or to provide additional emphasis for regulatory, warning, or guidance messages provided by other devices.

Support. EPG 913.3.4 contains information for arrow pavement markings in the vicinity of grade crossings.

Standard. Word, symbol, and arrow markings shall be white and retroreflective, except as otherwise provided in EPG 620.2.19.

Option. Black contrast markings may be used in combination with white pavement markings on light-colored pavements, such as concrete, to enhance visibility.

Standard. Pavement marking letters, numerals, symbols, and arrows shall be installed in accordance with the design details in the Pavement Markings chapter of the FHWA’s “Standard Highway Signs” publication (see EPG 911 (MUTCD Section 1A.05)).

Guidance. Word, symbol, and/or arrow markings that are grouped together to formulate one interrelated message should not exceed three lines of information.

Except for the two opposing white arrows of a two-way left-turn lane marking (see Figure 620.2.2), the longitudinal space between word, symbol, and/or arrow markings that are used together to formulate one interrelated message should be four times the height of the characters.

When conveying mandatory messages, these markings should only be used as supplementary devices to the standard signs.

Pavement word, symbol, and arrow markings should be no more than one lane in width.

Pavement word, symbol, and arrow markings should be proportionally scaled to fit within the width of the facility upon which they are applied.

Option. On narrow, low-speed shared-use paths, the pavement words, symbols, and arrows may be smaller than suggested, but to the relative scale.

620.2.20 Word Pavement Markings (MUTCD Section 3B.21)

Guidance. Letters and numerals should be 6 feet or more in height, except as provided in EPG 914.5.1 for the BIKE LANE word pavement marking.

The spacing between pavement word and symbol markings is approximate and should be adjusted as field conditions warrant.

If a pavement marking word message consists of more than one line of information, it should read in the direction of travel. The first word of the message should be nearest to the road user.

Standard. The word STOP shall not be placed on the pavement in advance of a stop line, unless every vehicle is required to stop at all times.


The image shows an example of elongated letters for the word “ONLY” as a pavement marking. The image includes dimensions of the elongated word message.
Figure 620.2.20 Example ONLY word pavement marking

Guidance. Where through lanes approaching an intersection become mandatory turn lanes, ONLY word pavement markings (see Figure 620.2.20) should be used in addition to signs (see EPG 903.2.25 and 903.2.26) and the required lane-use arrow markings (see EPG 620.2.22).

Option. The ONLY word marking may be used to supplement the lane-use arrow markings in lanes that are designated for the exclusive use of a single movement such as turn bays.

The ONLY word marking may be used to supplement a preferential lane word or symbol marking (see EPG 620.5.3).

Standard. The ONLY word marking shall not be used in a lane that is shared by more than one movement.

620.2.21 Symbol Pavement Markings (MUTCD Section 3B.22)

Support. EPG 914.5 contains information on symbol markings that can be used for bicycle lanes.

Option. Pavement markings simulating Interstate, U.S., State, and other official highway route signs with appropriate route numbers, but elongated for proper proportioning when viewed as a marking, may be used to guide road users to their destinations (see Figure 620.2.21.1).


Figure 620.2.21.1 Elongated Route Shields

A blue square is shown with rounded corners and with a white border, also with rounded corners. The blue background and white border are optional. Centered within the blue square is a white symbol of a person sitting in a wheelchair.
Figure 620.2.21.2 International Symbol of Accessibility Parking Space Marker

Figure 620.2.21.3 Yield Ahead Triangle Symbols


The image shows a black International Symbol of Accessibility (ISA) with a person in a wheelchair, displayed on a rectangular grid composed of 1-foot by 1-foot squares. A reference square at the top left indicates the 1-foot scale.
Figure 620.2.21.4 Disabled Symbol Detail


The image shows pavement markings for an accessible parking space with an adjacent access aisle. A white International Symbol of Accessibility (ISA) is painted within the parking stall. The access aisle is marked with 6-inch wide diagonal hash marks at a 45-degree angle, spaced 6 inches apart, with a minimum of three hash bars. Stall boundary lines are shown with 6-inch markings. The access aisle connects to a curb ramp that is yellow, with a minimum width of 60 inches, leading to a sidewalk. A blue-painted curb section indicates the placement of a disabled parking sign. White 4-inch markings are shown at the top of the space for boundary definition.
Figure 620.2.21.5 Disabled Parking Area


The image shows pavement markings for a row of accessible parking spaces with a shared access aisle. Four parking stalls are marked with the International Symbol of Accessibility (ISA), painted in white within each stall. The access aisle runs diagonally between the stalls and is marked with 6-inch wide diagonal hash marks at a 45-degree angle, spaced 6 inches apart, with a minimum of three hash bars. The access aisle has a minimum width of 60 inches. The accessible stalls each have a minimum width of 132 inches. Disabled parking signs are indicated along both sides of the row. At the bottom right, a detail shows 4-inch wide boundary markings.
Figure 620.2.21.6 Disabled Parking Area Multiple

Guidance. If route sign markings are provided to guide road users, those route sign markings should be provided in option lanes if markings are provided in any lanes.

If two route sign markings are provided in an option lane, they should be placed in sequence and not divided around an optional lane arrow.

Support. EPG 620.1.3 provides information on route sign colors.

Guidance. The International Symbol of Accessibility parking space marking (see Figure 620.2.21.2) should be placed in each parking space designated for use by persons with disabilities.

Option. A blue background with white border may supplement the wheelchair symbol as shown in Figure 620.2.21.2.

A yield-ahead triangle symbol or YIELD AHEAD word pavement marking may be used on approaches to intersections where the approaching traffic will encounter a YIELD sign at the intersection.

Standard. The yield-ahead triangle symbol or YIELD AHEAD word pavement marking shall not be used unless a YIELD sign (see EPG 903.2.5) is in place at the intersection. The yield-ahead triangle symbol marking shall be as shown in Figure 620.2.21.3.

Option. A pedestrian symbol pavement marking may be used on portions of facilities that are reserved exclusively for pedestrian use, such as where a shared-use path transitions to become separate facilities for different types of users.

620.2.22 Lane-Use Arrows (MUTCD Section 3B.23)

Figure 620.2.22.1 Examples of Arrows for Pavement Markings


Figure 620.2.22.2 Examples of Lane-Use Control Word and Arrow Pavement Markings

Support. Lane-use arrow markings (see Figure 620.2.22.1) are used to indicate the mandatory or permissible movements in certain lanes (see Figure 620.2.22.2) and in two-way left-turn lanes (see Figure 620.2.20).

EPG 913.3.4 contains information about the placement of lane-use arrow markings in the vicinity of grade crossings.

Guidance. Lane-use arrow markings should be used in lanes and turn bays designated for the exclusive use of a turning movement, except where engineering judgment determines that physical conditions or other markings (such as a dotted extension of the lane line through the taper into the turn bay) clearly discourage unintentional use of a turn bay by through vehicles. Lane-use arrow markings should also be used in lanes from which movements are allowed that are contrary to the normal rules of the road (see Drawing B in Figure 620.2.13.1).

The placement of arrows in channelizing lanes should be determined by the length of the lane and the following criteria (see Figure 620.2.22.3):

A. The first arrow should be placed 75 ft. in advance of the stop line.
B. The second arrow should be placed 200 ft. in advance of the stop line.
C. Any additional arrows should be placed in 200 ft. increments.

The distances between arrows may be adjusted if there are special circumstances that warrant the change.


Figure 620.2.22.3 Spacing of Arrow in Left-Turn and Right-Turn Lanes


Support. An arrow at the downstream end of a turn lane can help to prevent wrong-way movements.

Standard. Where through lanes approaching an intersection become mandatory turn lanes, turn lane-use arrow markings (see Drawing A in Figure 620.2.8.10 and Figure 620.2.22.1) shall be used and shall be accompanied by standard signs (see EPG 903.2.33) and the required ONLY word pavement markings (see EPG 620.2.20).

If used, the ONLY word pavement marking shall be placed in advance of each lane-use arrow for mandatory turn lanes or in advance of a preferential lane word or symbol marking.

Guidance. Where through lanes approaching an intersection become mandatory turn lanes, the required ONLY word markings (see Figure 620.2.20), signs (see EPG 903.2.25 and 903.2.26), and turn lane-use arrow markings should be placed well in advance of the turn and should be repeated as necessary to provide the through motorist advance notification to vacate the lane prior to reaching a point where roadway geometrics or a queue of waiting vehicles forces the motorist to make an unintended turn.

Spacing between the arrow and the ONLY should be four times the height of the ONLY. The use of ONLY should not apply to exit ramps.

Option. On freeways or expressways where a through lane becomes a mandatory exit lane, lane-use arrow markings may be used on the approach to the exit in the dropped lane and in an adjacent optional through-or-exit lane if one exists.

Guidance. The use of straight arrows should be reserved for special cases, such as, locations where crashes have occurred as a result of vehicles making turns from the through lanes.

620.2.23 Wrong-Way Arrows (MUTCD Section 3B.24)

Guidance. Where crossroad channelization or ramp geometrics do not make wrong-way movements difficult, the appropriate lane-use arrow should be placed in each lane of an exit ramp near the crossroad terminal where it will be clearly visible to a potential wrong-way road user (see Figure 903.2.39.1).

Option. The wrong-way arrow markings shown in Drawing G in Figure 620.2.22.1 may be placed near the downstream terminus of a ramp as shown in Figure 903.2.39.1, or at other locations where lane-use arrows are not appropriate, to indicate the correct direction of traffic flow and to discourage drivers from traveling in the wrong direction.

Directional pavement arrows may be used as a substitute for the wrong-way arrows when wrong-way arrows are required.

A maximum of two wrong-way arrows may be provided on a ramp, the placement of the second arrow is dependent upon the design and length of the ramp. Exit ramps that do not contain islands at the intersection of the exit ramp and the crossroad may receive one wrong-way pavement arrow at the top of the ramp. Ramps constructed with islands at the intersection of the exit ramp and the crossroad may receive two wrong-way arrows at the top of the ramp, one arrow on each side of the island.

Wrong-way pavement arrows may be placed on one way outer roads to further indicate the proper direction to travel.

Standard. In the case of two lane ramps where wrong-way pavement arrows are used, one arrow shall be provided for each lane.

Guidance. If used, the point of the wrong-way arrow should be located a distance of 25 ft. from the end of the ramp and the intersecting crossroad. When wrong-way arrows are used on one-way outer roads, the arrows should be installed 25 ft. in advance of the point where the edge of the crossroad and the outer road meet. Where a stop line has been provided, the arrow should be placed 25 ft. in advance of this marking.

On ramps where directional pavement arrows have been provided to aid the motorist in proper lane usage, the wrong-way pavement arrows should not be used.

620.2.24 Chevron and Diagonal Markings (MUTCD Section 3B.25)

Figure 620.2.24 Typical Chevron and Diagonal Markings


Support. Chevron or diagonal markings are used to discourage travel on certain paved areas, such as shoulders, neutral areas, and flush median islands.

Guidance. Chevrons should be installed in the neutral area of gores when the following conditions are present:

A. A gore length of 250 ft or greater; and
B. Exit lanes depart from through lanes at a low angle leaving a long distance between the theoretical and physical gore (See Drawing B in Figure 620.2.8.1).

Chevrons installed in the neutral area of gores should include a minimum of 3 chevron lines with 50 ft spacing consistent with the note on sheet 1 of Standard Plan 620.

Chevrons should not be used when there is less than 6 feet of distance between channelizing lines to avoid markings that are not identifiable as a chevron.

Option. Chevron and diagonal markings may be used:

A. On approaches to obstructions in the roadway (see Figure 620.2.15.2),
B. For channelized travel paths on approaches to intersections,
C. In buffer spaces between preferential lanes and general-purpose lanes (see Drawing A in Figure 620.5.2.2), and
D. In the neutral areas of islands.

Support. EPG 912 (MUTCD Section 5B.02) contains information on chevron markings for driving automation system considerations.

Standard. Chevron markings shall be white, with the point of each chevron facing toward approaching traffic, as shown in Figures 620.2.8.1 through 620.2.8.3, Figures 620.2.8.4 through 6202.8.3.6, and Drawing C in Figure 620.2.15.2.

Option. Diagonal markings for opposing directions of traffic may be used:

A. On approaches to obstructions in the roadway (see Drawings A and B in Figure 620.2.15.1),
B. In flush median islands between double solid yellow center line markings (see Figure 620.2.3.3), and
C. In buffer spaces between preferential lanes and general-purpose lanes (see Drawing D in Figure 620.5.2.5).

Diagonal markings may be used on paved shoulders or in no-parking zones, or other locations for special emphasis.

Standard. When diagonal markings are used between opposing directions of traffic or on the left shoulder of a one-way or divided roadway, they shall be yellow and slant away from traffic in the adjacent travel lanes, as shown in Figure 620.2.1.2 and Figure 620.2.3.3, and Drawings A and B in Figure 620.2.15.1.

When diagonal markings are used on the right shoulder or in no-parking zones (see Figure 620.2.26), they shall be white and slant away from traffic in the adjacent travel lane.

Except as provided in the second Option paragraph below, chevrons and diagonal markings shall be 24 inches. The longitudinal spacing of the chevrons or diagonal lines shall be 50 feet, with a minimum of three chevron or diagonal markings being used per application. The chevrons and diagonal lines shall form an angle of approximately 45 degrees with the longitudinal lines that they intersect.

Option. If there is insufficient space to install a minimum of three chevron or diagonal markings at 50 foot longitudinal spacing, the longitudinal spacing may be reduced.

Diagonal markings used in no-parking zones or on roadways with operating speeds of less than 25 mph may be 4 inches wide (see Figure 620.2.26).

620.2.25 Do Not Block Intersection Markings (MUTCD Section 3B.26)

 

Figure 620.2.25 Do Not Block Intersection Markings


Option. Do Not Block Intersection markings may be used to mark the edges of an intersection area that is in close proximity to a signalized intersection, railroad crossing, or other nearby traffic control that might cause vehicles to stop within the intersection and impede other traffic entering the intersection. If authorized by law, Do Not Block Intersection markings with appropriate signs may also be used at other locations.

Standard. If used, Do Not Block Intersection markings (see Figure 620.2.25) shall consist of wide solid white lines 8 to 12 inches wide that outline the intersection area that vehicles must not block and white cross-hatching 4 in. to 6 in. wide within the intersection area.

Do Not Block Intersection markings shall be accompanied by one or more DO NOT BLOCK INTERSECTION (DRIVEWAY) (CROSSING) (R10-7) signs (see EPG 903.2.48), one or more Do Not Stop On Tracks (R8-8) signs (see EPG 913.2.7), or one or more similar signs.

620.2.26 Parking Space Markings (MUTCD Section 3B.27)

Standard. On-street parking space markings shall be white.

Support. Examples of on-street parking space markings are shown in Figure 620.2.26.

Support. Additional parking space markings for the purpose of designating spaces for use only by persons with disabilities are discussed in EPG 620.2.21 and illustrated in Figure 620.2.21.2.

Figure 620.2.26 Example of Parking Space Markings

620.2.27 Speed Hump and Speed Table Markings (MUTCD Section 3B.29)

Figure 620.2.27.1 Pavement Markings for Speed Humps without Crosswalks


Figure 620.2.27.2 Pavement Markings for Speed Tables or Speed Humps with Crosswalks


Guidance. Speed humps and speed tables are generally not used on MoDOT-maintained facilities. Districts should contact the State Highway Safety and Traffic Engineer for approval prior to installation.

Standard. If speed hump markings are used, they shall be a series of white markings placed on a speed hump to identify its location. If markings are used for a speed hump that does not also function as a crosswalk or speed table, the markings shall comply with Option A, B, or C shown in Figure 620.2.27.1. If markings are used for a speed hump that also functions as a crosswalk or speed table, the markings shall comply with Option A or B shown in Figure 620.2.27.2.

Option. Where used, center line markings, lane line markings, and edge lines may be discontinued on the profile of the speed hump.

Standard. Where a speed hump or a speed table specifically incorporates a crossing movement for pedestrians, bicyclists, or equestrians, and functions as a raised crosswalk, crosswalk markings (see EPG 620.3) shall be provided.

620.2.28 Advance Speed Hump and Speed Table Markings (MUTCD Section 3B.30)

Guidance. Advance speed hump markings are generally not used on MoDOT-maintained facilities. Districts should contact the State Highway Safety and Traffic Engineer for approval prior to installation.

Option. Advance speed hump markings may be used in advance of speed humps or other engineered vertical roadway deflections such as dips where added visibility is desired or where such deflection is not expected.

Advance word pavement markings such as BUMP or HUMP may be used on the approach to a speed hump either alone or in conjunction with advance speed hump markings. Appropriate advance warning signs may be used in compliance with EPG 903.6.22.

Standard. If advance speed hump or speed table markings are used, they shall be a series of eight white 12-inch transverse lines that become longer and are spaced closer together as the vehicle approaches the speed hump or other deflection.

Guidance. If used, advance speed hump markings should be installed in each approach lane.

620.2.29 Aircraft Speed Measurement Markings

Support. An aircraft speed measurement marking is a transverse marking placed on the roadway to assist the enforcement of speed regulations.

Standard. Aircraft speed check markings shall only be installed after the District Engineer or the District Engineer's representative receives a request from the Missouri State Highway Patrol. A member of the Highway Patrol shall be present when these stations are placed to verify their location and spacing for legal purposes.


This figure shows a two-lane roadway with a solid yellow centerline and dashed white lane lines. On each side, there is a yellow or white edge line depending on direction of travel. The roadway includes pairs of 24-inch by 24-inch white square pavement markings spaced across both lanes, set 660 feet apart. A third set of markings is optional at the Highway Patrol’s request. An arrow legend indicates direction of travel along the roadway.
Figure 620.2.29 Pavement Marking for Aircraft Speed Check Stations

Speed measurement markings, if used, shall be white, and shall be 24 in. x 24 in. and the distance between the blocks shall be 660 ft., measured from the leading edge of the first block to the leading edge of the second block. This distance shall be measured on the actual pavement surface and is the same for all posted speeds (See Figure 620.2.29).

The markings shall be reflective, and are to be placed on the center of each driving lane.

Those markings, which have been improperly installed shall be removed by one of the methods noted in EPG 620.11.4.

Option. A third block may be installed at the special request of the Highway Patrol.

If the Highway Patrol wishes to only check traffic flowing in one direction, these markings may be omitted from the opposing lanes.

Guidance. Aircraft speed check markings should receive periodic inspection to ensure they are maintained in an acceptable and functional manner. Existing aircraft speed check markings that are no longer in use should be allowed to deteriorate.

The application of any material should be done following the manufacturer’s recommendations for installation.

Option. On concrete surfaces, black may be used to provide contrast of the speed blocks.

620.2.30 Markings for a Diverging Diamond Interchange with a Transposed Alignment Crossroad (MUTCD Section 3B.31)

A diverging diamond interchange shows where two northbound lanes and two southbound lanes cross, transposing their alignments to each other in the middle of the interchange. At the top and bottom of the interchange, the lanes are in their typical alignment relative to each other. Right-turn “ONLY” and left-turn “ONLY” entrance lanes are shown merging into the lanes and right-turn “ONLY” exit lanes are shown turning away from the lanes. At the lane crossover intersections, dotted white and yellow lines separate the travel lanes from each other. Directional pavement markings indicate travel direction. Stop bars are shown ahead of crosswalks. Sidewalks with curb ramps are shown connected to crosswalks over raised islands that separate through travel lanes from the entrance and exit lanes.
Figure 620.2.30 Example of Pavement Markings for a Diverging Diamond Interchange with a Transposed Alignment Crossroad

Support. Markings used in a diverging diamond interchange with a transposed alignment crossroad can be advantageous for minimizing wrong-way movements. The potential for wrong-way movements is greatest at the crossover intersections where the alignment becomes transposed.

Standard. On the transposed alignment, each direction shall be considered a one-way roadway whereas the edge line convention shall be in accordance with EPG 620.2.10. Both yellow and white edge lines shall be used.

A lane-use arrow (see EPG 620.2.22) shall be used in each approach lane at the crossover intersection.

Support. EPG 620.3.9 contains information on crosswalks and pedestrian movements for diverging diamond interchanges with a transposed alignment crossroad.

Standard. Flush median islands (see EPG 620.9.3) shall not be used to divide the inverted flow of traffic.

Guidance. Edge line and lane line extensions (see EPG 620.2.13) should be provided through the crossing points.

Support. Figure 620.2.30 illustrates an example of pavement markings for a diverging diamond interchange with a transposed alignment crossroad.

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